The Value of Negativity
An earlier article here discussed the utility of Likert items. A Likert item consists of two parts: a stem, which is simply a statement of an attitude, and a scale on which people express their agreement with that statement. A problem that arises with Likert items is that people are reluctant to use negatively worded stems.
Employers, for example, may have no problem with letting their staff disagree with the statement I like my job, but be reluctant to give them the chance to agree with the statement I dislike my job. Since the two answers are equivalent, anyway, why should we bother to use negative items?
The reason they are used is to protect against response style bias. This is a bias in responding which is due to the form of the item. For example, some people are more compliant than others – they tend to agree with whatever statement is put before them. If you ask them to rate items which are all positively worded, they will agree with them, and if you asked them to rate a set of items which are the negatively worded opposite of the same items, they would agree with them, too. By mixing up positive and negative items you get them to pay attention to the content of the items.
There is no reason to worry about people getting confused and using the rating scale incorrectly, either. People readily understand that agreeing with a negative is the same as disagreeing with a positive, and so on.